Magnesium chloride catalyst for modified urea resins



MAGNESKUM CHLORIDE CATALYST FOR MQDIFIED UREA RESINS Theodore F. Cooke,Martinsville, Louis J. Moretti, Somerville, and Robert C. Conn, BoundBrook, N. J., assignors to American Cyanamid Company, N ew York, N. Y.,a corporat on of Maine No Drawing. Application September 28, 1955 SerialNo. 537,289

11 Claims. (Cl. 117139.4)

The present invention relates to stable aqueous solutions of certainmodified urea resins containing magnesium chloride as a catalyst andfinishing textiles with such mixtures.

Textile materials have long been treated with certain resins to impartvarious desirable qualities such as wrinkle resistance and shrinkresistance. To expedite the curing of the impregnated fabric and toprovide a waterinsoluble finish, it has been customary to add acatalytic agent to the treating bath in order to obtain curing timessufiiciently short for large-scale commercial operations. The usualcatalysts have been either acidic in nature or latent acid-formingsubstances. Even the latter develop an acid condition in a textiletreating pad bath with the passage of time, and pad bath stability hasbeen a continuing problem in the industry. In addition, it has not beenpossible to pre-mix a catalyst with the resins which are usually sold asconcentrated aqueous solutions because of the instability of suchmixtures. This instability is manitested in solutions becoming turbid orhydrophobing, after a comparatively short time. A one-package premixedtextile finishing agent and catalyst would be advantageous to thetextile finisher in reducing his problems of preparing a pad bath inproper proportions.

An object of the invention is to provide stable aqueous solutions ofcertain resins containing magnesium chloride.

Another object of the invention is to provide concentrated premixedaqueous solutions of certain modified urea resins premixed withmagnesium chloride as a catalyst.

A further object of the invention is to provide relatively diluteaqueous solutions of certain modified urea finishing agents and acatalyst which have exceptional stability.

Still another object of the invention is to provide an apparent to thoseskilled in the art, especially upon consideration of the detaileddisclosure hereinbelow.

The above and other objects and advantages are obtained with the presentinvention which comprises astable aqueous dilute or concentratedsolution contain-j magnesium chloride and at least one agent of thegroup'- consisting of methylated methylol urea, partially poly-flu"merized methylated methylol urea, methylated and un'-' methylatedmethylol ethyleneureas and methylated and unmethylated methylol1,2-propyleneureas. The invention also includes treating textilematerials with such solutions and curing the impregnated material toconvert 2,846,337 Patented Aug. 5', 1958 ICQ 22 the agent to thewater-insoluble state. In addition, it encompasses textile treatmentswherein the impregnated fabric is dried and mechanically finished morethan twenty-four hours later followed by a curing operation.

The catalyst-containing mixtures of the present invention produce anumber of beneficial effects. They impart a high degree of wrinklerecovery and shrink resistance to a wide variety of fabrics. Moreover,pad baths containing these mixtures have outstanding stability againsthydrophobing, separation, or gelling. Also, the preparation of pad bathsis greatly simplified by the high stability of the mixtures inconcentrated aqueous solution which permits their sale in a singlepackage rather than separately as catalysts and finishing agents. Longaging of the concentrated solutions does not cause separation or impairthe effectiveness of the resins for imparting shrink resistance andwrinkle resistance.

The treatments ofthis invention are applicable to a wide variety offabrics and textile fibers including woven, knitted, felted, andnonwoven fabrics. If desired, the application may be made to raw fibersor to yarns or threads. However, it is preferred to treat one of theabove-mentioned fabrics to obtain the optimum benefits of the invention.The fiber content of the fabric may comprise any of the cellulose fibersincluding cotton, viscose rayon, cuprammonium rayon, flax and ramie;wool; nylon of both the adipamide and caprolactam types, as well asrelated super polyamides; homopolymers and copolymers of acrylonitrile;polyester fibers such as cellulose acetate, including cellulosetriacetate, polyethylene glycol terephthalate and other syntheticfilaments.

The greatest utility of the finishing treatments appears to be withcotton and rayon fibers and blends thereof with other textile fibers.

The invention is specific to certain modified urea resins, which term isused herein to include partially or wholly methylated methylol ureas andtheir water-soluble lower polymers as well as methylol ethyleneurea,methylol 1,2- propyleneurea and methyl ethers of these cyclic ureas.These resins commonly contain from about 1.3 to 2 mols of combinedformaldehyde per mol of urea or cyclic urea. In the case of the methylethers, the degree of methylation (that is, the percent of availablemethylol groups which are converted to methoxymethyl groups) may rangefrom about 30 up to Other resins such as methylated or unmethylatedmethylol melamine and unmodified urea-formaldehyde do not possess astability of the same order in admixture with magnesium Conventionalcatalysts for textile resins such as amine hydrohalide salts, ammoniumsulfate, various ammonium-phosphates, ammonium chloride, and acids suchas oxalic and orthophosphoric acids all form solutions with the modifiedurea resins which are comparatively acid either initially or afterstanding for a comparatively lim- :ited period. Accordingly, these arenot suitable for use in premixed resin-catalyst concentrated blends.Also, pad baths prepared with such catalysts have a relatively limitedlife.-

. For maximum stability the pH of the aqueous resinmagnesium chloridesolution, either concentrated or as dilute as about 2% solids, should bebetween about 7.0 and about 10.5; and this may be adjusted, ifnecessary, by the addition to the mixture of a small amount of magnesiumhydroxide or any compatible alkaline material such as the carbonates,bicarbonates, or hydroxides of sodium, potassium, or ammonia, amines andother organic bases. Above a pH of about 10.5, an undesirable turbidityis produced. Such alkalinity corresponds to a content of about 1% orless magnesium oxide based on the total Weight of anhydrous magnesiumchloride. A similar etlect is not obtainable with mixtures of theseresins with other catalysts, inasmuch as the alkalinity seriouslyimpairs the catalytic effect of such other catalysts.

In preparing premixed finishing agents containing catalysts, it isdesirable to have as concentrated a product as possible in order tominimize shipping costs; hence, the resin solids content should rangefrom about upward and preferably between about 60% and 90% by weight.The magnesium 'chloride content may vary between about 2% and about 25%based on the weight of the resin solids. Pad baths commonly containbetween about 2.5 and about resin solids, but the concentration may beas low as about 1% or as high as about 50% or more where a stiff finishis sought.

The treatment may be carried out in conventional manner with the add-onor deposit of resin on the fabric controlled by selecting the proper padbath concentration for a particular textile material and regulating thepressure applied to the squeeze rolls. While the dry pickup may rangefrom about 1% to about 50%, a deposit of between about 2% and about 25%based on the dry fiber weight is recommended for most purposes. Afterimpregnation, the fabric may be dried and cured either simultaneously orin separate operations. The curing may be accomplished by exposing thefabric to temperatures between about 275 F. and the point at whichdegradation in the particular fabric commences, usually above 400 F.,for a period sufficient to convert the finish to a substantiallywater-insoluble state. In general, temperatures of about 275 to 375 F.for periods between about 30 seconds and about 30 minutes arerecommended. Curing by exposure to much hotter radiant elements for abriefer period is also suitable, inasmuch as the temperature of thefabric is doubtless about the same as produced in ovens operating atlower temperatures. If a separate drying operation is employed,temperatures of about 180 F. to about 250 F. are suitable for mostpurposes. After curing, the textile material may be subjected to aconventional process wash to remove any unreacted resin; but this is notnecessary, as fabrics treated according to this invention are notsubject to acid degradation and have no tendency to pnoduce dermatitis.

After a treated fabric has been dried at a temperature below that atwhich curing of the finish takes place, it may be stored forconsiderable periods without any deleterious eifects such as developingodor or a reduction in the final wrinkle resistance and shrinkresistance. This is an outstanding feature which is not possessed byother resin-catalyst mixtures, inasmuch as the treated fabric may bedried in one plant and then transported considerable distances toanother plant for mechanical finishing or allowed to stand untilproduction conditions permit large-scale embossing or pleatingoperations. While pleating machines, embossing rolls, Schreiner andfriction calenders and other equipment capable of producing athree-dimensional configuration or a glazed finish are commonly heatedto a degree which undoubtedly produces at least some curing, it isthought best to insure complete curing by subjecting a fabricmechanically finished in this manner to a complete curing operation, asset forth above, to stabilize the finish against laundermg.

For a better understanding of the nature and objects of the presentinvention,'reference should .be had to the following examples whereinall proportions are given in terms of weight unless otherwise specifiedtherein. These examples illustrate the invention and are not to beconstrued as limitations thereon.

EXAMPLES Concentrated aqueous resin solutions are mixed withconcentrated aqueous solutions of various catalysts to produce mixturesof active ingredients in the proportions set forth in the table below.The resin designated MMU is essentially monomeric methylated dimethylolurea or bismethoxymethyl urea, and PMMU stands for a water-solublepartially polymerized 70% methylated dimethylol urea. The latter resinis prepared by mixing 10.3 mols of water, 37.5 mols of methanol and 63.5mols of 91% paraformaldehyde with sufficient triethanolam'ine to producea pH of 8.2, adding 28.4 mols of urea and refluxing for 2% hours at 175F. After cooling to F., 88.5 mols of methanol is added, and the pH isadjusted to 3 with oxalic acid. After refluxing at 162 F. for 25minutes, the reaction mixture is neutralized with triethanolamine andconcentrated under vacuum.

The dimethylol ethyleneurea designated by DMEU is prepared in knownmanner charging 2 mols of formaldehyde per mol of ethyleneurea andcontains a relatively small amount of uncombined formaldehyde. The aminecatalyst in the table hereinbelow consists of hydrochloride salts ofmixed isopropanolamines. -The stability of the resin-catalyst mixturesis determined over various periods at three different temperatures inboth the concentrated state and after dilution with water to a contentof 5% solids. Stable samples show no turbidity, separation orcrystallization when concentrated and no hydrophobing with the formationof a precipitate or turbidity upon dilution. The diluted mixtureapproximates the concentration of the pad baths in which fabricsundergoing a resin treatment are immersed and the concentrated form is aone-package resin treatment in salable form which requires only dilutionto the desired pad bath strength. Comparative examples denoted byletters are given for comparison with the numbered examples of thepresent invention.

Table Weight percent Stability in Days at Example Resin Solids CatalystSolids Water 50 C. 37 0. 25 C.

58.7 PMMU. 34.4 63.0 PMMU" 26.3 65.3PM1\IU 4 30.7 69.6 PMMU" 2 28.0 27.9MMU. a ass 28.3 MMU 1. 70. 0 20.0 MMU.-- 1. 10. 0 42.2 DMEU- 5 52.8 44.4DMEU 1. 48.1 45.5 DMEU 3.1 51.8 41.5 DMEIL- 1.7(NH4)=SO4- 50.8

1 Yellow-orangeeolor develops on aging. I Orystaillzes and yellows onaging.

The solution in Comparative Example A is on the acid side, B has a pH of6, and C has a pH of 4.3, whereas the mixture of Example 1 has a pH of7.9 after standing three days. The examples demonstrate the outstandingstability of the novel mixtures in contrast with those containing othercatalysts.

The examples hereinbelow are carried out by diluting certain of the agedresin-catalyst mixtures described in the above table sufiiciently toprovide a dry pickup of 5% resin solids on 80 x 80 cotton percale (145wrinkle recovery untreated) and on rayon gabardine in a con ventionalpad bath with the squeeze rolls set for 83% expression. All samples aredried at 225 F. and the dry impregnated cotton percale is cured for 1.5minutes at 350 F. while the rayon gabardine is cured for 3 minutes at300 F. in a ventilated oven. In the case of the cotton material, onlythe wrinkle recovery is determined by the roller pressure method andonly the hand of the rayon is evaluated.

For comparison, certain lettered examples are set forth using freshlyprepared resin which is mixed with the catalyst immediately prior totreating the fabric.

EXAMPLE 4 Freshly prepared PMMU resin and a solution of magnesiumchloride are mixed in a pad bath and diluted to a concentration of 6%resin solids and 0.72% magnesium chloride. After treatment therewith,the cotton percale is found to have a wrinkle recovery of 216 and therayon gabardine has a soft hand.

EXAMPLE 5 A resin-catalyst mixture according to Example 1 is aged forover one year at 25 C. and then diluted to a resin solids content of 6%to form the pad bath. Cotton percale finished with this mixture has awrinkle recovery of 220, and a similarly finished rayon gabardine hasthe same hand as the sample in Example 4. It is apparent that nodeterioration of the resin-catalyst mixture results from aging over anextended period prior to application.

EXAMPLE 6' A pad bath is made up to a content of 6.0% DMEU solids from afresh commercial product and 0.72% magnesium chloride. The wrinklerecovery of cotton percale finished therein is 252, and the hand of asimilarly treated rayon gabardine is soft.

Mercerized cotton yarn is passed through the same pad bath and dried andcured in the same manner. This yarn is fed to a loom for weaving percaleas the warp with an untreated mercerized cotton yarn being fed as thefilling. The resulting novelty percale has substantially improvedwrinkle recovery and shrink resistance.

EXAMPLE 7 A sample of the resin of Example 3 after aging for more thanone year at 25 C. is diluted to a concentration of 6.6% total solids.After treating the cotton percale and rayon gabardine samples therewith,it is found that the cotton has a wrinkle recovery of 252, and the handof the rayon is only slightly firmer than the finished rayon of Example6.

EXAMPLE J A pad bath is prepared by diluting a regular commercial sampleof DMEU resin to 6.0% in a bath containing 0.36% mixed isopropanolamineshydrochlorides solids. Cotton finished with this mixture is determinedto have a wrinkle recovery of 259 and rayon gabardine has a softresilient hand.

EXAMPLE K A discolored sample of a mixture according to Example G isdiluted to a total solids content of 6.3% after aging for over one year.The hand of a rayon fabric treated with this mixture is equivalent tothat of Example I, but the wrinkle recovery of cotton fabric is only211.

EXAMPLE 8 An x 80 cotton percale is padded through an aqueous pad bathof pH 8.2 containing a solution of 8% DMEU resin and 1% magnesiumchloride with the pad rolls adjusted for-a 100% wet pickup. Theimpregnated fabric is thoroughly dried at 225 F. and then stored for onemonth. At the end of this time, the impregnated but uncured material issprayed lightly to bring the moisture content of the material up toabout 10% by weight. A sample of the impregnated fabric is cut off andsoaked in a small quantity of water to extract the uncured finishtherefrom. The pH of this aqueous extract is found to be slightly above7 indicating that the uncured fabric is substantially neutral ratherthan acidic in nature. Next, the moistened material is passed through apleating machine. After pleating, it is placed in an oven maintained at325 F. for 1.5 minutes in order to insure that curing is complete. Thematerial is found to have an excellent resilient hand and a permanentpleat which is extremely resistant to mussing, shrinkage and wrinkling.Upon repeating the operation with no appreciable lapse between thedrying step and the pleating, a fabric is obtained with a finish equalin all respects to that of the first sample. pleated and cured materialsis the same indicating that storing the uncured impregnated fabricresulted in no tendering.

What we claim is:

1. A composition of matter which comprises a stable, aqueous solutionfor treating textile materials'having a pH between 7.0 and 10.5,consisting essentially of magnesium chloride as the sole catalyticcomponent and a small amount of a compatible alkaline materialcorresponding to a content of magnesium oxide up to about 1%, based onthe total weight of anhydrous magnesium chloride, and from between 1 andabout by weight of an agent selected from the group consisting ofmethylated methylol urea, partially polymerized methylated methylolurea, methylated and unmethylated methylol ethylene ureas and methylatedand unmethylated methylol 1,2-propylene ureas, said magnesium chloridebeing present in said solution in an amount of from between about 2 and25%, based on the weight of the agent solids.

2. A composition according to claim 1 comprising a pre-mixed finishingcomposition containing between about 60 and about 90% by weight of agentsolids.

3. A composition according to claim 1 comprising a pad bath containingbetween about 2.5 and about 30% by weight of agent solids.

4. A composition according to claim 1 in which the agent is methylatedmethylol urea.

5. A composition according to claim 1 in which the agent is partiallypolymerized methylated methylol urea.

6. A composition according to claim 1 in which the agent is methylolethylene urea.

7. A process which comprises impregnating a textile material with astable, aqueous solution having a pH between 7 and 10.5, consistingessentially of magnesium chloride as the sole catalytic component and asmall amount of a compatible alkaline material suflicient to producesuch alkalinity corresponding to a content up to about 1% of magnesiumoxide, based on the total weight The tensile strength of both I of thetextile material, and curing the material by exposure to a temperatureabove 275 C. and below the point at which degradation of the textilematerial commences, for a period sufficient to convert the agent to theWater-insoluble state, whereby a finish resistant to wrinkling andshrinkage is imparted to the textile material.

8. A process according to claim 7 in which a fabric containingcellulosic fibers is treated with methylated methylol urea.

9. A process according to claim 7 in which a fabric containingcellulosic fibers is treated with partially polymerized methylatedmethylol urea.

10. A process according to claim 7 in which a fabric containingcellulosic fibers is treated with methylol ethylene urea.

11. A process which comprises impregnating textile material with astable, aqueous solution having a pH between 7 and 10.5, and consistingessentially of between 2.5 and about 30% by weight of an agent selectedfrom compatible alkaline material sufiicient to provide such alkalinityand corresponding to an amount up to about 1% of magnesium oxide, basedon the total weight of anhydrous magnesium chloride, in sufficientamount to deposit thereon between about 20 and 25% of said agent, basedon the weight of the dried textile material, drying the impregnatedtextile material at least partially, pressing the impregnated materialmore than 24 hours after the impregnating operation and while themoisture content is between about 5 and 20%, based on the weight of thedried textile material, and curing the material by exposure to atemperature of above about 275 F. and below the temperature at whichdegradation of the textile material commences for a period sufficient toconvert the agent to the water-insoluble state, whereby a material ofsub stantially permanent wrinkle resistance and shrinkage resistance isobtained. 3

References Cited in the file of this patent UNITED STATES PATENTS l2,254,001 Conaway Aug. 26, 1941 2,373,136 Hoover Apr. 10, 1945 2,653,921Sulzer Sept. 29, 1953 2,661,312 Richardson Dec. 1, 1953 2,709,141 BurksMay 24, 1955

11. A PROCESS WHICH COMPRISES IMPREGNATING TEXTILE MATERIAL WITH ASTABLE, AQUEOUS SOLUTION HAVING A PH BETWEEN 7 AND 10.5, AND CONSISTINGESSENTIALLY OF BETWEEN 2.5 AND ABOUT 30% BY WEIGHT OF AN AGENT SELECTEDFROM THE GROUP CONSISTING OF METHYLATED METHYLOL UREA, PARTIALLYPOLYMERIZED METHYLATED METHYLOL UREA, METHYLATED AND UNMETHYLATEDMETHYLOL ETHYLENE UREAS AND METHYLATED AND UNMETHYLATED METHYLOL1,2-PROPYLENE UREAS, AND A QUANTITY OF MAGNESIUM CHOORIDE AS THE SOLECATALYSTIC COMPONENT, AMOUNTING TO BETWEEN ABOUT 2 AND ABOUT 25% OF THEWEIGHT OF SAID AGENT, AND A SMALL AMOUNT OF A COMPATIBLE ALKALINEMTERIAL SUFFICIENT TO PROVIDE SUCH ALKALINITY AND CORRESPONDING TO ANAMOUNT UP TO ABOUT 1% OF MAGNESIUM OXIDE, BASED ON THE TOTAL WEIGHT OFANHYDROUS MAGNESIUM CHLORIDE, IN SUFFICIENT AMOUNT TO DEPOSIT THEREONBETWEEN ABOUT 20 AND 25% OF SAID AGENT, BASED ON THE WEIGHT OF THE DRIEDTEXTILE MATERIAL, DRYING THE IMPREGNATED TEXTILE MATERIAL AT LEASTPARTIALLY, PRESSING THE IMPREGNATED MATERIAL MORE THAN 24 HOURS AFTERTHE IMPREGNATING OPERATION AND WHILE THE MOISTURE CONTENT IS BETWEENABOUT 5 AND 20%, BASED ON TEH WEIGHT OF THE DRIED TEXTILE MATERIAL, ANDCURING THE MATERIAL BY EXPOSURE TO A TEMPERATURE OF ABOVE ABOUT 275*F.AND BELOW THE TEMPERATURE AT WHICH DEGRADATION OF THE TEXTILE MATERIALCOMMENCES FOR A PERIOD SUFFICIE%NT TO CONVERT THE AGENT TO THEWATER-INSOLUBLE STATE, WHEREBY A MATERIAL OF SUBSTANTIALLY PERMANENTWRINKLE RESISTANCE AND SHRINKAGE RESISTANCE IS OBTAINED.